Method of printing and article resulting therefrom



June 21 1938` R. T. K. coRNwELL 261211221 METHOD OF" PRINTING'AND ARTICLE RESULTING THEREFROM Filed Aug. 23, 17955v .3 Cow/770mm@ V ATTORNEYS Parentedjune 21, 1938 PATENT ori-lolaI METHOD -OF PRINTING AND ARTICLE RE-A SULTING THEREFROM Ralph 'I'. K. Cornwell, -signor to Sylvania Fredericksburg, Va., as- Industrial Corporation,

Fredericksburg, Va., a corporation of Virginia Application August 23, 1935, Serial No. 37,526

8 Claims.

'The invention relates in general to the formation of indicia and in particular to a process of printing upon a, pellicle of a hydrophilic colloid while in the gel condition, and

deposit was not sufliciently dense and the edges' of the indicia were diffuse. It has alsoI been 15 suggested to produce indicia on films of "hydrophilic colloids while in adrycondition by direct printing with inks containing opaque pigments, such as titanium oxide'. In this process, the deposit is formed only on the surface of the ma- 20 terial, so that the indicia show very little adhesion to the base, and frequently bleed and flake oli when the article is immersed in water.

It is a general object of the invention to provide articles formed of non-fibrous material capable of forming a hydrogel with an indicium which is characterized by being relatively permanent, strongly adherent when immersed in water n and difficult toV alter or remove, and a process for the production thereof.

A more specific object of the invention is to provide shrinkable container closuresformed of I a hydrophilic colloid, with indicia comprising 4a dense deposit of color having a substantial depth of penetration and sharpness of outline, and a process for the production of such closures.

Other objects of the invention will in part be obvious and will in-part appear hereinafter.

The. invention accordingly comprises the several steps and the relation lof one or more of such steps with respect to each of the others, and the article possessing the features and properties which are exempliiied in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

According to the invention, an indicium of satisfactory density, depth and sharpness o outline may be produced on a non-brous material capable of forming a hydrogel and especially a 5 hydrophilic colloid in the gelk state by impregagent'therefor and which is also a solvent for the dyestuif employed in the ink, and then printing the impregnated material with an ink or corn-l 55 position containing a substantive or direct dyeincludes cor- 5 related improvements designed-to enhance the' nating the colloid with a water-miscible swelling stuff preferablyvcarried in a water-miscible yvehicle.

The expressions gel state and gel condition are employed herein to designate the condition of a pellicle of a hydrophilic colloid which has been impregnated with a water miscible swelling agent therefor and which is also a solvent' for substantive dyestuffs.

For a more complete understanding of the nature and objects of the invention, reference vshould be hadv to -the accompanying drawing, in

which:

Fig. 1 is a diagrammatic representation of an apparatus for carrying out certain steps of the process;

Fig. 2 is an illustration of aA seamless tube formed of a hydrophilic colloid which has been printed inaccordance with the invention;

Fig. 3 is a view oi a printed shrinkable closure band: and

Fig. 4 is a view cap. y

The vprocess of the invention may be applied for printing various hydrophilic colloids in the gel those cellulose ethers which swell in water and dissolve in alkalies; gelatine, casein and the like. The cellulose hydrate may be derived from .vis-l cose solutions or solutions of cellulose in cupraammonia or in zinc chloride. The hydrophilic colloid may be in the form of sheets, films, hollow bodies such, for example, as capsules, or seamless, exible tubing which is adapted to be used as sausage casings or which may be severed in'to short lengths to form shrinkable closure bands.A The process is also applicablek for printing nonbrous materials which are capable ofv imbibing water and forming a hydrogel,

A suitable dyestuif solvent is one which is miscible with water, preferably hygroscopic, and capable of penetrating the hydrophilic colloid, such, for example, as polyhydric alcohols such as glycerine, ethylene glycol, diethylene glycol, and ethers of the glycols-such as methyl, ethyl, butyl, etc., and organic nitrogen compounds' derivable from ammonia, such, for example, as the amines, amides, tetraamonium compounds, especially the alkyl and hydroxyl derivatives `of these compounds such `as the ethanolamines. Thus-the article to be printed may be first conditioned by immersing it in a bath containing 50%of water and 50% of monoethyl ethervof ethylene glycol.` The dyestuff solvent Whichi's'incorpo-r'ated in the gel may be the same as or'diierent from that used in the ink. Further, since the ink vehicle o-f a printed shrinkable closure state such; for example, as cellulose hydrate; 2

is water-miscible, the hydrogel may be impregnated with the entire ink vehicle, if desired, in lieu of impregnating it only .with thel dyestuif solvent'.

Water adheringto the surface of the article after the solvent impregnation is removed before printing, preferably by drying the surface as by passing a blast of warm air thereover, but care should be taken that the gel is not dried throughout. Preferably the gel is printed while it is at a temperature Vhigher than atmospheric to increase the rate of penetration of the dyestuif.

The surface-dry and conditioned gel is printed with an ink containing a substantive dyestui, such as is used for the direct dyeing -of cotton and other forms of cellulose, dissolved in a watermiscible solvent. Suitable dyestuffs are those known as benzo form, plutoform black, formyl colors, diamine-aldehyde colors, of which the following may be given as examples: benzo fast red L and GL, benzo fast yellow, benzo pure blue, Columbia blue, benzo fast blacks, diamine deep black, oxydiamine black.

'Ihe dyestuff is selected so as to have a high solubility in the water-miscible solvent and a relatively low solubility, or to be insoluble, in water. Preferably thereis used la dyestui of which the fastness to light andiwater can be improved by a suitable after-treatment such, for example, as a treatment with an aqueous formaldehyde solution. In some cases the stability of the dyestuif to light and water may be increased further by treatment with copper sulphate or potassium dichromate. It is preferable to wash the dyestuiT thoroughly in orderto remove inorganic salts which are commonly present therein. If such salts are permitted to remain in the dyestuif, they tend to crystallize within the material and detract' from the strength and trans-e parency of the hydrophilic colloid.

The dyestufl' is carried in a water-miscible vehicle containing a water-miscible solvent for the dyestui, water, and preferably also an organic hygroscopic agent which may be also a solvent of the dyestuif. 'I'he water in the ink vehicle promotes the penetration -of the dyestuil' into the hydrogel structure. For the hygroscopic agent there may be employed a non-crystalline organic substance, for example a polyhydric alcohol, such as glycol, glycerine, or diethylene glycol; triethanolamine; and other known hygroscopic agents. If desired, the ink may be thickened by the addition of a thickening agent such as a gum, dextrine, starch, and the like.

By way of illustration, the fllowing examplesv of a suitable inktcomposition are presented:

Ink vehicles Percent Butyl Water I of cellulose hydrate is passed from the supply roll 2 through a' vat 3 which may contain a mixture of about parts of monoethyl ether of The tube conditioned with the solvent then.

passes through the printing unit designated generally as 5, which comprises a heated roller 6, a pair of printing rollers 1 and 8 between which the tube passes, the roller8 being provided with a raised design to which ink is applied from the inking rollers 9 and I0, the latter of which dips into the vessel I I containing the ink.

After the printing operation, the printed material may be and preferably is aged for a time suilicient to produce the desired penetration of the dyestuii.' into the hydrogel. 'I'he penetration may be accelerated, for example by heating the printed material for about one minutevor longer according to the penetration desired. Thus, the printed tube may be passed into and festooned in a chamber I2 heated to from 60 to 90 C. the traverse `being completed in one minute. In lieu of heating, the material may be allowed to stand in air for a longer period of time. During the ageing, the dyestuif solvent should not be completely removed. Further, the penetration of the dyestuif is. promoted by the presence of the solvent in the hydrogel.

Immediately after the ageingv operation, the printed tube may be and preferably is immersed in a salt solution which renders the dyestuif insoluble and thus prevents smearing and bleeding .of the indicia. For example, the tube may be passed through a vat I3 containing a 5%-10% aqueous solution of calcium chloride. After the salt treatment, the printed tube may be passed into a vat I4 containing water which washes off any excess ink and extracts the residual dyestu solvent.

'I'he printed material may now be placed in a vat I5 containing a 3% aqueous solution of formaldehyde maintained at a temperature of from 60 to 90 C. for about 30 minutes. The tube is then given a final washing in a vat (not shown) containing water and a small amount of an alkali to neutralize any acid remaining in the material. The printed and washed tube, which is still in a gel state, may be employed as sausage casing, and in this event it is subjected to the usual softening and drying treatments.

Alternatively, the printed tube I'may be severed along thev lines IS-IBT, asshown in Fig. 2, to form a shrinkabl'e closure band I1, such as that illustrated in Fig. 3. When destined for use as bands, it is preferable to cut the tube as soon as possible after the printing operation, for example, at thel point C shown in Fig. 1. 'I'he subsequent treatments of ageing, salting, washing and fixing may then be carried out as separate batch operations.

It is to be understood that the process is not restricted to the printing of seamless tubing,'but is equallyapplicable for the printing of sheets,

lms, and hollow bodies suchas capsules, in particular shrinkable closurecaps I8, as shown in Fig. 4.

Since certain changesl in carrying out the above process, and certain modications in the article which embodies the invention may be made without departing from itsscope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a l limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and vention which, asa matter of language, might be' said to fall therebetween.

I claim:- 1. A process for producing an indicium on a pel'licle of a hydrophilic colloid, comprising impregnating such a colloid with an organic -watermiscible dyestufl solvent which is a swelling agent for said colloid and printing the thus .impregnated colloid in gel 'state with an ink containing a substantive dyestuff soluble in said solvent.

2. A process for producing an indicium ona pellicle of a hydrophilic colloid, comprising'impregnating such a colloid Vwith an organic watermiscible dyestuff solvent which is 'a swelling agent for said colloid and printing thethus impregnated colloid in gel state with an ink con- 'taining a substantive dyestuif soluble in said solvent and a water-miscible solvent therefor.

3. A process for producing an indicium on a `pellicle of a hydrophilic colloid, comprising impregnating such a colloid with an organic watermiscible dyestuff vehicle which is a swelling agent for said colloid, printing the thusimpregnated colloid in gel state withyan ink containing a substantive dyestuil" vsoluble in said vehicle and a water-miscible vehicle therefor, and thereafter xing said dyyestuflv in the colloid. l

1 4. A process for producing an indicium on a pellicle of a hydrophilic colloid, comprising impregnating such a colloid with an organic watermiscible dyestui solvent which is a swelling agent for said coll'oid, printing the thus impregnated colloid in gel state with an ink containing a substantive dyestuff soluble in said solvent and a water-mlscible solvent therefor, ageing the printed material whereby thedyestui is diiused, and thereafter fixing the cdyestuff.

5. A process for producing an indicium 4on a pellicle of a hydrophilic colloid, comprising impregnating such ay colloid with an organic waterv' miscible dyestui solvent which is a swelling agent for said colloid and printing the thus impreg-` nated colloid in gel state in the presence of heat with an ink containing a substantive dyestui soluble in said solvent and a `watermiscible solvent thereforf.

6. A process `for producing an indicium on a pellicle of a hydrophilic colloid, comprising impregnatin'g such a colloid with an organic watermiscible dyestuif solvent which is a swelling agent for said colloid, removing surface liquid from said impregnated colloid, heating and printing said impregnated colloid in gel state with an ink containing a substantive dyestui soluble in said solvent and a water-miscible solvent therefor. ageing the printed material and insolubilizing the dye impregnated in said material.

7. A process for producingan indicium` on a pellicle of a non-brous material capable of forming a hydrogel, comprising impregnating said material with an organic water-miscible dyestuff solvent which is a swelling agent for said material, printing the thus impregnated material in gel state with an ink containing a substantive dyestuif `soluble in said solvent, ageing said impregnated material, thereafter washing and fixing said dyestuffin the material. l

8. A process for producing an indicium on a pellicular article formed of cellulose hydrate, comprising impregnating such an article with an organic water-miscible dyestui solvent which is a swelling agent for cellulose hydrate and then printing said article in vgel state with an ink con- 

